The present invention relates generally to push ram assemblies. More specifically, this invention relates to push ram assemblies that are capable, in one embodiment, of allowing for a longer stroke while minimizing disturbances or shaking.
Ram assemblies may be used to push or move articles, such as cans. For example, ram assemblies may be used to push a can that is being processed in a curling, cutting, expanding, neck, or other forming operation machine.
Conventional ram assemblies comprise a cylindrical or round ram, which moves axially relative to the turret shaft, and a plain bushing, which is mounted fixed to the shaft. The ram can be moved by a ribbed barrel cam. However, such conventional rams can have limitations at longer strokes. For example, one such limitation is due to the pressure angle of the cam. At longer strokes, the pressure angle increases. This higher pressure angle puts a higher side load on the ram and bushing, which can cause the ram to bind in the bushing. Another downfall of conventional ram assemblies is that a can or other article being pushed by the ram assembly may enter a forming die at an incorrect angle, which can cause defects in the can. In a long stroke application, conventional ram assemblies require a larger clearance between the ram and the bushing. The clearance allows the end of the ram, which controls the position of the can, to move. This larger clearance may cause the can to enter the forming die at an angle causing defects in the can.